Such devices are, for example, used on endless conveyor belts made from synthetic material members of any width, for loosening these out of an operationally suitable slightly tensioned condition or for tensioning these into an operationally suitable condition. This occurs when the distance between two deflection rollers, over which the conveyor belt is guided, is reduced or enlarged. The loosened condition of the conveyor belt can facilitate different processes, such as, for example, maintenance work on the conveyor belt, in particular the cleaning. For this, a raising of the conveyor belt by means of a suitable aid can additionally be useful.
Different solution attempts were already proposed in the past for loosening and stretching of endless conveyor belts. For example, in NL 9002835 A a construction is proposed, in which the distance between the deflection rollers is changed on a plane parallel to the direction of travel of the belt. Characteristic of the device proposed in NL 9002835 A is that it keeps the conveyor belt in tensioned condition under a constant operational tension and, for example, compensates for temperature dependent stretching or contraction.
As a further example, in DE 42 33 131 A1, a device for tensioning and loosening of an endless conveyor belt is disclosed, in which one of the deflection rollers is arranged on a swivelling-supported tension lever. Through swivelling of the tension lever, the distance changes between the deflection rollers, and the conveyor belt is tensioned or loosened.
Furthermore, devices for tensioning and loosening of an endless conveyor belt are currently utilized, in which the distance between the deflection rollers is changed manually on a level parallel to the direction of travel of the belt. The deflection roller to be displaced is able to be manually loosened from a frame of a conveyor belt conveying system and guided displaceably. Such devices do not guarantee that the deflection roller is evenly displaced, i.e. the same in the direction of travel left and right.
As well as the devices for tensioning and loosening of endless conveyor belts, supporting structures are currently utilized, which support the conveyor belt in its course between the deflection rollers in the carrying of its own weight and the weight of the goods transported on its surface. For deflection rollers which are able to be loosened, a gap between the support construction and the deflection roller is provided, so that the deflection roller does not collide with the support construction when loosening. These gaps can result in an unclean operational run occurring and increased wear and tear on the conveyor belt.
The object of the present invention is therefore to provide a device for tensioning and loosening of an endless conveyor belt which is guided over deflection means, which guarantees that in operation the conveyor belt is supported also between the displaceable deflection means and the support construction. Preferably the displacement of the deflection roller should occur evenly.